Americans are at last trading in their wasteful behemoth cars, SUV's and trucks for more EFFICIENT and EFFECTIVE vehicles. Honda and Mercedes are amongst the leaders in building efficient and effective vehicles which still can delight with their road manners.
Even Toyota is suffering because like the US Big 3, its model program includes some behemoth SUV's and trucks.
It would be interesting to see Mercedes' US sales figures broken down by model. I would suspect that the recent increasing sales are in the V6 powered models as well as the new Diesel offerings.